GB2250459A - Adjustable diameter precision boring tool - Google Patents

Abstract

The tool comprises a cylindrical cartridge (10, 10') having a longitudinal or angled bore (1) therein and a second bore (2) transverse thereto with a tool shank (50) carrying a tool tip (51) slidable within it. A rotatable control knob (43) rotates a micrometric screw (30) in the bore (1) which extends through an axial bore in a toothed segment (20) and is screw threaded into a bushing (24). Rotation of the screw causes axial movement of said toothed segment. Angled teeth (22) on the toothed segment engage with corresponding teeth (52) on the tool shank to move the shank transversely. Both the screw (30) and the segment have backlash preventing means. <IMAGE>

Description

2250439 ULTRA-PRECISION SUB-MICRON BORING TOOL AND PRE-SETTING SYSTEM

BACKGROUND OF THE INVENTION

The invention refers to a ultra-precision submicron boring tool and presetting system or device and more specifically to a sub-micron boring tool and pre-setting system or device that when rotating at very high speed and within ultra precision performs the finish machining operation of boring of ultra precision blind and through bores on parts that are preferably stationary, but not limited to, as to their rotating movement.

In accordance with the present state-of-the-art, to meet ultra-precision requirements, the positive or negative deviations permitted in relation to a preestablished theoretical nominal dimension either for components or f or micrometric pre-setting can not exceed I micron.

Several types of devices f or tool pre-setting are known and widely used, however, in general all of them are built with their operating knob and mechanisms actuating directly on the tool shank, which does not provide enough accuracy sensibility to fine setting and also are not satisfactory as to consistent pre-setting repeatability and are not provided with means to eliminate backlash.

1 These deficiencies found on conventional pre-setting devices do not allow a very precise and fine micrometric setting (within the micron magnitude) of the cutting tool in relation to the workpiece, makIng it difficult and slow the finish machining operation of high precision bores.

It is an object of the present invention to provide a boring tool which reduces inconveniences.

According to the present invention there is provided a boring tool comprising a substantially cylindrical body having a first, substantially longitudinal bore therein, and a second bore opening in the circumferential surface of said body and intercepting said first bore, a tool shank for carrying a tool tip being movably received within said second bore, and a rotatable control knob carried by said body for enabling the positionof the tool shank in said second bore to be set, and further comprising means provided in said first bore for moving said tool shank, said moving means being coupled to said control knob and being arranged to move said tool shank in said bore in response to rotation of said control knob.

With an embodiment of the invention the control knob actuates the tool shank indirectly in a sequence of subsequent steps or phases, as is explained below.

Furthermore, the tool edge can be pre-set with ultra high accuracy by way of the ultra-precision sub-micron boring tool control knob thereby eliminating the need for any additional pre-setting as is required when using stateof-the art boring tool devices.

Preferably, the tool edge position of a rotatable tool is preset, the preset dimension being the distance between the most distant or farthest point on the tool edge and the geometric axis of rotation around which the tool revolves.

In an embodiment the present invention provides a submicron boring and tool pre-setting system whose construction enables the elimination of backlash of the whole assembly, also embodying a motion reducing mechanism or motion demultiplier mechanism which imparts displacement to the tool shank in an indirect manner, which enables and assures superfine micrometric pre-setting of the tool shank and guarantees precise, repeatable and wholly consistent pre-setting of cutting tool edge corresponding to increments of a micron on diameter for finish machining ultra precision bores, and which additionally enables that the degree of fineness or precision of reading, that is, that the magnitude of submicron increments be obtainable through choice at the time of the demultiplying ratio is established at the design stage, because the referred magnitude of increment decreases at an inverse proportion as the demultiplying ratio increases.

The present invention may also provide a sub-micron system for boring tool and tool pre-setting that offers an extremely simple means to set-up tool displacement to determine the bore diameter to be machined, enabling that such setting be made in reduced time without trial and error and that backlash elimination is accomplished in such a way that always and wherever displacing movement of moving parts occurs in the mechanism inside the sub-micron system through the whole kinematics, i.e., starting up from the turning of a control knob down to the tool edge, all contact surfaces of all parts involved that cooperate together, that is, work coupled so that through the displacement of referred contact surfaces they slide, ones in relation to the others, under a metal to metal contact condition to set (to accomplish and establish) the tool edge position determining and establishing a distance that corresponds to the farthest point from the tool edge in relation to its geometric axis of rotation in such a way that due to metal to metal contact between the sliding surfaces of all sliding parts involved, it is positively assured that said displacement of parts are always exempt of lost motion, backlash and/or deviations of any nature or magnitude, which is a basic, indispensable and unquestionable condition to accomplish the ultra-precision pre-setting and to assure consistent ultra- fidelity of presetting repeatability within ultra-precision standards.

According to a further aspect of the present invention there is provided a sub-micron tool boring and pre-setting system provided with a motion reducing mechanism or motion demultiplier mechanism, which imparts displacement to the tool shank for finishing either blind or through bores, the system comprising a cylindrical cartridge to operate at high speed, being 1 actuated by a machine tool spindle to perform finish machining operations of precision bores with a single point tool, maintaining the workpiece stationary as to its rotating movement, being that the work feed can be achieved either by axial movement of the machine tool spindle maintaining the workpiece stationary as to feed movement or by axial feed on the workpiece, said axial feed being parallel to the geometrical axis of the cylindrical cartridge, being this last one stationary as to the feed mot.ion.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Drwg. 1 is a longitudinal view of the sub-micron boring tool and presetting system in a first form destined preferably for finishing through bores; Drwg. 2 is a longitudinal view of the sub-micron system, taken from line A-A of drawing 1; 1 6 Drwg. 3 is a cross section of the sub-micron system taken from line B-B of drawing 2; Drwg. 4 is a cross section taken from line B-B of drawing 2, however illustrating an alternative construction format for the tool shank; Drwg. 4a is a cross section taken from line C-C of drawing 4; Drwg. 4b is an enlarged detail of drawing 4.

Drwg. 4c is an enlarged detail of cross section illustrated in drawing 4b, being illustrated the reaction of efforts between the parts during backlash adjustments of the sub-micron system; Drwg. 5 is a longitudinal section of the submicron boring tool and pre- setting system in an alternative solution destined preferably for finishing blind bores; drawing 5; drawing 6; clamping.

Drwg. 6 is a cross section taken from line D-D of Drwg. 7 is a cross section taken from line E-E of Drwg. 8 is a detail of cutting tool clamping; Drwg. 9 is another detail of cutting tool DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with these drawings, the sub-micron boring tool and presetting system subject of the present invention is provided with a motion reducing mechanism or motion demultiplier mechanism consisting of two toothed segments which teeth have converging flanks, and a micrometric screw which is also useful for tool presetting, destined preferably for finish machining of through bores as illustrated in drawings 1, 2, 3, 4, 4a, 4b and 4c and for the alternative solution destined preferably for finish machining of blind bores as illustrated in drawings 5, 6 and 7.

Another objective of the present invention is obtained with the constructive arrangement for cutting tool clamping, illustrated in drawings 8 and 9 and described further on in which the field of work between the smallest and largest machining diameters can be further increased enabling the use of the same device for several bore diameters.

The sub-micron boring tool and pre-setting system for finishing preferably through bores, illustrated in drawings 1, 2, 3, 4, 4a, 4b and 4c consists of a main body in the format of cylindrical cartridge 10, internally hollow by bore 1 stepped along the length of its body where toothed segment 20 is lodged; micrometric screw 30, both arranged on a common geometric axis, being said micrometric 8 screw 30 provided with threaded external section 31 in one of its ends which is free to pass through an axial bore in toothed segment 20 and coupled with internal thread 21 provided in bushing 24, being said bushing 24 lodged and internally retained by extension 25 through hollow stud 26, being said extension 25 fixed at one end of toothed segment 20 by thread 20a; ring 40 that supports micrometric screw 30; spacer ring 41, ring 42 that also supports micrometric screw 30; rotation control knob 43 that is supported by micrometric screw 30 close to the other end of this micrometric screw; locknut 44 provided with fastening stud 44a and pad 44b, threaded on thread 32 provided externally on the other end of micrometric screw 30, and locating ring 13 lodged at the end of cylindrical cartridge 10 and covered by protection 14.

Seeing drwg. 3 it is noticed that cylindrical cartridge 10 incorporates another bore 2 located preferably, but not limited to, at a right angle, being said bore 2 possible to be inclined or oblique in relation to the geometric axis of said cylindrical cartridge 10, being in said bore 2 lodged tool shank 50 provided with tool 51 tightened by screw 55 acting on clamp 551.

According to drwg. 2, bushing 24 is provided with male tapered section 24a in its ends, which adjust to corresponding female tapered sections 25a. and 26a provided internally respectively in extension 25 and hollow stud 26 and is still provided with slotted sections 24b 9 longitudinally slotted in its body on both sides and inserted between themselves in such a way that the slots starting from one and do not go through the other and.

Backlash elimination between the thread of micrometric screw 30 and internal thread 21 provided in bushing 24, is accomplished by tightening hollow stud 26 which when turned in the internal thread provided in extension 25, it presses bushing 24 between female tapered sections 25a and 26a which when actuating male tapered io section 24a and in cooperation with slotted sections 24b impose a contraction, causing an elastic decrease in the outside diameter of bushing 24, and consequently decreasing also the diameter of internal thread 21 which involves the thread of micrometric screw 30 until it eliminates entirely the backlash between said threads, however, allowing that the micrometric screw may be smoothly rotated.

Pin 27 radially f ixed in extension 25 with its free end fitted in one of the slotted sections 24b provided in bushing 24, avoids that said bushing 24 may rotate in relation to said extension 25.

In the larger diameter represented by longitudinal bore 3 of cylindrical cartridge 10, are lodged without clearance ring 40, spacer ring 41 and ring 42 which constitute the bearing system on which micrometric screw 30 rotates and is supported radially and axially, being said rings 40, 41 and 42 fixed by screws 45 which go through v 1 these last ones and are threaded in the back wall which defines the length of bore 3.

In this way ring 40 and ring 42 act as radial bearing to micrometric screw 30 in its medium portion, being the support bearing in radial direction acting as bearing without clearance of portion 33 of micrometric screw 30 in corresponding bore of ring 40, being the thrust bearing in the axial direction consisting of adjoining faces of rings 40 and 42 which spaced by spacer ring 41, retaining collar 35 of micrometric screw 30 between sections 33 and 34 supressing, therefore, any axial play of said micrometric screw 30.

Micrometric screw 30 incorporates at its outer end to the cylindrical cartridge 10, a tapered seat 36 with converging diameter (reduction) towards the outer end of said micrometric screw 30, being that to said tapered seat 36, the knob 43 is solidarily coupled permitting its radial and axial positioning, said positioning being assured through tightening of locknut 44, which in turn is securely fastened or locked by thread 32 of micrometric screw 30 through stud 44a and pad 44b, being this last one made of brass or any other material of less hardness appropriate for assuring proper locking without damaging fillets of thread 32.

As shown in drwg. 1, externally and at the periphery of rotation control knob 43, at the rim adjacent to cylindrical cartridge 10, it is engraved scale 43a 11 graduated with engraved equidistant lines to be used as a means for reading the displacement of tool 51 when knob 43 is manually turned, having as reference index or point 43b engraved at protection cover 14 adjacent to referred graduated scale 43a.

With this type of tapered coupling between micrometric screw 30 and knob 43, that is, the coupling of knob 43 in the tapered seat 36, it is possible to provide in a selective way the zeroing or reset of graduated scale 43a in relation to index 43b, to establish a certain edge position of tool 51 in relation to the geometric center of cylindrical cartridge 10 in order that the-zero in graduated scale 43a coincides with index 43b_. After zeroing or resetting, rotation control knob 43 is set in tapered seat is 36 through lock nut 44, once said knob 43 is solidarily joined to micrometric screw 30.

Returning to drwg. 2, it is seen that turning by hand rotation control knob 43 and consequently micrometric screw 30, threaded section 31 of this last one, which engages in internal thread 21 of bushing 24, causes axial sliding of toothed segment 20 along bore 1 of cylindrical cartridge 10, which sliding can be selectively made in both directions indicated by arrows X and Y, depending on the direction of rotation of knob 43.

It is seen in drwgs. 2 and 3 that with the axial sliding of toothed segment 20, in relation to cylindrical cartridge 10, radial displacement movement is imparted to 1.

1 12 tool shank 50 through a notion demultiplier mechanism, defined by indentation 22 in an approximate rack fashion, provided externally in toothed segment 20 in a plane secant to its cylindrical body being said indentation 22 longitudinally indented and with slight inclination QQ. in relation to its geometric axis, which teeth 22 mesh in a sliding manner totally free from any backlash to corresponding teeth 52, provided in a secant plane of the cylindrical body of tool shank 50.

Based on drwgs. 1 and 2, in order to cause an increment in the depth of cut, that is, a radial displacement of tool shank 50, rotating control knob 43 is turned by hand in the direction of arrow I so that threaded section 31 causes axial displacement in toothed segment 20, in the direction of arrow X and indentation 22, being slightly inclined and in close contact with teeth 52 of tool shank 50 it causes radial displacement of said tool shank 50 in relation to cylindrical cartridge 10 in the direction of arrow Z. In the same manner, the withdrawal of tool shank 50, that is, its displacement in the direction of arrow W is made by turning rotating control knob 43 in the direction of arrow R. ' As shown in drwg. 3, to assure accurate displacement and to guarantee a stable position of tool shank 50 in relation to cylindrical cartridge 10, it is provided resilient backlash eliminator system 60 provided with spring 61 lodged in hole 53 provided in tool shank 50 1 0 body, so that one end of said spring 61 actuates at the inner end of stud 62 threaded in the entrance of hole 53 and the other end of said spring actuates on end 63a of stud 63 threaded in hole 4 provided in cylindrical cartridge 10 body, being that end 63a of stud 63 enters hole 53 through opening 54 provided in tool shank 50 body. In this way, spring 61 acts on stud 62 and reacts at end 63a of stud 63, keeping tool shank 50 always forced in the direction of arrow W.

Therefore, the described sub-micron system can be coupled either directly to the machine main spindle and/or coupled to a shank extension in the case of machining deep holes, being this shank extension coupled to the machine spindle.

As illustrated in drwgs. 1 and 2 when the device is coupled to shank extension 70, the coupling end of cylindrical cartridge 10 is provided with a recessed section with threaded portion 5 and centering portion 6.

Therefore, cylindrical cartridge 10 is fixed in shank extension 70 by screwing threaded portion 5 to corresponding internal threaded portion 71 of said shank extension 70, being the screwing tighteness obtained by resting extreme face 72 of shank extension 70 on face 7 defined in this end of cylindrical cartridge 10.

Centering and perfect alignment of cylindrical cartridge 10 with shank extension 70, are assured by precision fitting of centering portion 6 perfectly 13 1 concentric with geometric axis of cylindrical cartridge lo, in a corresponding bore provided in the interior of shank extension 70 also perfectly concentric with geometric axis of said shank extension 70, and by resting extreme face 72 of this last one on extreme face 7 at a square (right) angle of longitudinal axis of cylindrical cartridge 10.

When machining deep bores and when the sub-micron system remains stationary as to feed movement, seat 37 provided concentric in the free end of micrometric screw 30, makes possible to the device to rest on the machine tailstock 73, totally eliminating overhang and further ensuring rigidity to the device which is an important condition for precision machining.

Tailstock 73 even when equipped with live center may cause slight resistance due to friction at the cone of seat 37 with tendency of rotating micrometric screw 30 in relation to cylindrical cartridge 10, tending to accidentally change pre-set radial distance GF- EG, GFI-EG.' during machining. To avoid accidental alteration of pre-set distance GF-EG, GFI-EGI control knob 43 is provided with ratchet indent 43c in its face adjoining extreme face of cylindrical cartridge 10, which teeth are coupled to ratchet indent 13a provided at face of loaded spring locating ring 13, being this last one lodged in a sliding manner at the end of cylindrical cartridge 10, pressed against ratchet indent 43c through loaded springs 15, and radially retained 14 i 1 by pin 16 which avoids turning of said ring 13 in relation to cylindrical cartridge 10.

When control knob 43 is manually turned, the turning action of ratched indent 43c which teeth profile are notched with converging flanks to the direction of the teeth top, actuating in ratched indent 13a, which teeth profile are also notched with flanks converging to the direction of the teeth top, ring 13 is displaced towards arrow 13b (drwg. 2) disconnecting said ratched indent 43c and 13a. Having said ratched indents 43c and 13a a number of teeth, which may either be double or any multiple of the number of divisions of graduated scale 43a, assures that when the ratched indents are again coupled to subsequent ratched indents, the maximum radial displacement of rotation control knob 43 is half or any sub-multiple of the value read between two adjacent lines of graduated scale 43a.

Considering that the sub-micron system is useful for ultra precision machining where it is required an extremely low level of vibration during operation and that said sub-micron system operates at very high speeds, cylindrical cartridge 10 is provided with a balancing system to balance rotating masses as shown in drwg. 3, being said system comprised of, as an example and without limitation, two blocks 80 and 81 lodged in slot 8 provided at the middle of cylindrical cartridge 10 and positioned in a secant plane parallel in relation to the geometric axis of bore 2, being said blocks 80 and 81 provided with elongated openings 82, 16 that can be trespassed by fastening screws 83 which allow the displacement, positioning and fastening of blocks 80 and 81 in slot 8 during balancing operation. Even though it is not shown in drwg. 4, said balancing system is also applicable in the constructive alternative shown in said drawing and described further on.

The body of cylindrical cartridge 10 also incorporates in the periphery in secant position but at a substantial square (right) angle to bore 2, rounded slot 9 which provides lodging space for screw 55 which clamps tool tip 51 onto tool shank 50 as shown in drwgs. I and 3.

Drwgs. 4, 4a, 4b and 4c show a constructive alternative of the sub-micron system for finish machining of preferably through bores. As shown in drwg. 4b,.backlash elimination (backlash suppression) between teeth 22, provided in toothed segment 20, and teeth 52-1 provided in tool shank 501, is accomplished in a positive way, that is, having said teeth 22 and 521 interact in a forced way, one against the other, through the adjustment of indented plunger 90 precision lodged and slidable. in axial bore 531 provided internally in the body of tool shank 501, being said indented plunger 90 provided with teeth or indentation 91 in the same plane of teeth 521 of tool shank Sol and actuating teeth or indentation 22 of toothed segment 20.

Backlash elimination between teeth, schematically illustrated in drwg. 4b, is accomplished by adjusting stud 92, which is threaded in an internal thread provided in tool 1 shank 5V, being that the adjustment of stud 92 displaces indented plunger 90 in relation to tool shank 501 in the direction of arrow 93, causing flanks 94 of teeth 52f provided in tool shank 50.' to rest against flanks 22a of teeth 22 provided in toothed segment 20, and flanks 95 of teeth 91 provided in indented plunger 90 to rest against flanks 22b of teeth 22 provided in toothed segment 20.

Once the adjustment is made through stud 92 so that the teeth f lanks are put in contact under a metal to metal condition, totally free from any backlash but still allowing a smooth sliding of toothed segment 20 and tool shank 501, stud 92 is locked through tightening of lock stud 96.

Considering the set of parts 20, 90, 50f and 92, illustrated in drwgs. 4, 4a and 4b, and as already explained, by moving forward stud 92 by rotating it in the interior of shank 501, it also pushes forward indented plunger 90 forcing it to travel in the direction indicated by arrow 93 and while the body where said stud 92 rotates, the body of tool shank Solis simultaneously forced or pushed to travel in the direction indicated by arrow 93a, that is, in opposite direction that indented plunger 90 travels.

In accordance with drwg. 4b the relative movement of the two parts 90 and 50f in opposite directions with the teeth of each of them, that is, teeth 521 of tool shank 501 and teeth 91 of indented plunger 90, acting on opposite flank2 22a and 22b of teeth 22 of toothed segment 20 and the is 17 1 special profile of teeth flanks being themselves not parallel but being convergent flanks, they may have a triangular prismatic shape or the shape of involute or a files, or shape in which the flanks may be of unequal prol.

still of any other shape as long as the teeth thickness decreases as the profile approaches the converging line at the teeth top, causes the withdrawal or retraction of toothed segment 20 in the direction indicated by arrow 100 and withdrawal or retraction of parts 90 and 5011 in the direction of arrows 101 and 102 respectively, this retraction of parts 90 and 501 being in opposite direction of the direction of retraction of toothed segment 20.

Referring now to drwg. 4, being said parts 20 and 501 lodged in a slidable way in appropriate bores provided in cylindrical cartridge 10 and indented plunger 90 lodged also in slidable way in axial bore 530 of tool shank 501, the withdrawal movement will cease when all clearances have been suppressed, not only between the inclined teeth but also on one side between toothed segment 20 and cylindrical cartridge 10 and on the other side between indented plunger 90 and tool shank 501, against which indented plunger 90 is pushed by inclined teeth effect and finally, when all clearances have also been suppressed between shank 501 and cylindrical cartridge 10, against which tool shank 501 is pushed either by the inclined teeth or by the reaction effect of indented plunger 90 on tool shank So'.

18 1 At the instant a displacement of toothed segment 20 and tool shank 501is reached under a metal to metal sliding condition, with zero clearance and zero interference, a condition of absolute prevention of angular displacement of toothed segment 20 in relation to cylindrical cartridge 10 is established, because the bearing contact in opposite flanks 22a and 22b of teeth of toothed segment 2 0 in its external portion f orm with the center (axis) of micrometric screw 30, rectangular triangles A-B-C 19 and D-B-C, illustrated in drwg. 4c, where in points A and D of hypotenuses A-B and D-B, said teeth of toothed segment 20 are in contact metal to metal at points E and F of corresponding teeth 91, 52f of indented plunger 90 and of tool shank 50f, preventing angular movement of any nature or magnitude of toothed segment 20 even though at the lodging at bore 1 where toothed segment 2.0 slides in said bore 1 of cartridge 10, the periphery geometric shape, that is, the cross section configuration of toothed segment 20 as well as the mating geometric shape where said toothed segment 20 seats into bore 1 perpendicular to the sliding axis, correspond to a perfect circle and because toothed segment 20 has a flat plane cut secant and parallel to the axis of said toothed segment 20 and because said secant plane bears on a flat and parallel plane on tool shank 501 and indented plunger 90.

1 is Looking at drwgs. 2, 3 and 4b, the sliding action totally free from backlash or play of tool shank 50, 501 and toothed segment 20 at bores 2 and 1, respectively, the sliding ac tion also totally free from any backlash between the flanks of teeth 22, 52 or 22, 52f and 91, the rotation of micrometric screw 30 totally free from backlash at internal thread 21 and totally free from axial backlash, since the adjacent faces of rings 40 and 42 that are spaced by spacer ring 41 retain collar 35 of micrometric screw 30 between portions 33 and 34 prevent any magnitude of axial play of said micrometric screw 30 and finally the system consisting of all components involved and engaged to assure that the pre-set radial distance GF-EG, as seen in drwg. 4, is precisely maintained within the micron and assuring to all moving parts that their displacement is free from backlash thus assuring also stability to the position of the edge of tool 51 in a way to guarantee within the micron..A.. the GF-EG radial distance that goes from the tool edge farthest point to the geometric axis of cylindrical cartridge 10, around which in 3602 revolution precision repeatability is positively assured in constant way until tool wear occurs.

The sub-micron boring tool and pre-setting system for machining, in the alternative form of the invention for finishing preferably blind bores as illustrated in drwgs. 5, 6 and 7 is comprised basically of cylindrical cartridge 101, tool shank 50,101 toothed segment 20,1, bushing 24,1, 1 i micrometric screw 301, these last ones 201, 24t and30f arranged on a common geometric axis, ring 401 and spacer ring 41,1 that actuate as abearing for micrometric screw 300 and graduated dial 43f fitted on micrometric screw 30f through thumb screw 441.

Cylindrical cartridge 101 is provided with two seats 10 and 21 with substantially triangular adjacent sections, positioned at square (right) angle to each other and both inclined in relation to the geometric axis of rotation of cylindrical cartridge 10', according to P..0. and angles shown in drwg. 5.

According to drwg. 6, in seat 2f it is lodged in a sliding way tool shank 5011 which has its cross section in triangular shape having one of its faces provided with teeth 52n and one of its ends provided with cutting tool Sit.

In seat 11 it is lodged in a sliding way toothed segment 201, which cross section is also of triangular shape, being provided in one of its faces with teeth 22t which couples in a sliding way to teeth 52" provided with tool shank SO".

According to drwg. 5, in the interior of toothed segment 20f, it is lodged bushing 241 retained by hollow stud 26f, being said bushing 24f provided with internal thread 21f where it is coupled threaded end 31f of micrometric screw 301 which other end provided with an enlarged diameter in collar shape 351 with centering diameter 331 and centering projection 341, centering 21 1 projection 34t being integral with micrometric. screw 30f is supported radially and axially by centering rings 401 and 41t which are fastened through screws 451 on inclined face 121 provided MC the end of cylindrical cartridge 10,1 and positioned at square (right) angle to seat It.

Bushing 24f is of a barrel shape with its two ends tapered on diameter, which progressively narrows towards both ends, said tapered ends 24al that mate with corresponding female tapers 20af and 26al provided internally in toothed segment 20t and in hollow stud 2 6 t respectively, and it is also provided with slotted sections 24bl longitudinally cut in its body on both sides and inserted between themselves in such a way that the slots starting from one end do not go through the other end.

Backlash suppression between the male thread of micrometric screw 301 and female thread 211 provided in bushing 24f, is accomplished by tightening hollow stud 261, which when rotated in an internal thread provided in toothed segment 20t presses bushing 241 between female tapers 20al and 26al which when actuate on male tapered section 24at and in cooperation with slotted sections 24bt, they force a contraction imposing an elastic decrease of external diameter of bushing 241 and, consequently, also decreasing the diameter of female thread 21' which involves the thread of micrometric screw 30t until totally eliminating backlash between said threads, however, allowing that micrometric screw 301 can be smoothly turned.

22 1 Pin 27,' radially fastened to toothed segment 20. and with its free end fitted in one of the slotted sections 24bt provided in bushing 241, prevents that said bushing 241 can be turned in relation to said toothed segment 20f.

The bearing support at the end of micrometric screw 301 is accomplished radially by the fitting without play of centering diameter 331 in bore of ring 411, and axially by retaining without play collar 3511 between face 410 of ring 41f and inclined face 121, the latter provided at the end of cylindrical cartridge 10f, being that ring 40f acts as a spacer between said faces 4111 and 12f. Both the fitting of centering diameter 33,1 in bore of ring 411 and the holding of collar 351 between faces 121 and 4111 are accomplished without any clearance, however, in a way that allows micrometric screw 30f to be smoothly turned through thumb screw 441.

At centering projection 34f provided at the end of micrometric screw 301' it is centered graduated dial 4V, fastened by thumb screw 44,1 which besides fastening said graduated dial 431, it is also used as a knob to rotate micrometric screw 300. Once thumb screw 441 is tightened, graduated dial 431 and said thumb screw 441 are solidarily joined to micrometric screw 30f.

Turning micrometric screw 30f clockwise or counterclockwise, actuating manually on thumb screw 441, the threaded end of thread 3111 of said micrometric screw 301 which is coupled to internal thread 211 provided in bushing 23 1 241 causes a displacement to toothed segment 201 in the direction indicated by arrow X' or in the direction indicated by arrow Y1.

Teeth 52" provided in tool shank 5Ou and 22f provided in toothed segment 20/ are engaged between themselves and are cut at a slight inclination A. in relation to the longitudinal section of toothed segment 20f in such a way that with the displacement of said toothed segment 20f in the direction indicated by arrows X', Y1, the action exerted by inclination A. of teeth 5211 and 221 cause a displacement of tool shank 5011 in the direction indicated by arrows V, W, indirectly withdrawing or approaching the edge of tool 51f from or to the geometric axis of rotation of cylindrical cartridge 101 in the direction indicated by arrows K, L, resulting in an increment or in a decrement which corresponds to an increase or to a decrease in the depth of cut.

The special configuration of the cross section of tool shank SW' and toothed segment 201, which special profiles of flanks opposite to the face provided with teeth are not parallel between themselves but convergent, the cross section may have a triangular shape as illustrated in drwgs. 6 and 7 or the shape of an involute or the shape where the flanks are of unequal profiles or still any other shape, whenever the distance between the flanks of the cross section, measured parallel to the toothed plane, is decreasing as measurement is made in parallel lines 24 1 progressively approaching the converging point opposite to the f ace provided with teeth of the respective toothed segment 20f and of tool shank 500, and the configuration of teeth with inclined flanks of both indentatins 52w and 22f may have the shape of a tringular prism or the shape of an involute or the shape where the flanks are of unequal profile or still any other shape in which the tooth thickness decreases as the profile approaches the converging point at the tooth top, making possible that upon toothed segment 201 having been driven through two studs 6211, each one pressing a Bell6ville spring (disc spring) 61f acting. on face 23f of said toothed segment 20t, all clearances are totally and integrally eliminated between tool shank 5011 and its guide in seat 2f, also between toothed segment 201 and 'its guide in seat 10 and also between the flanks of teeth 5211 and 221, to the extent that the sliding of tool shank 5011, the sliding of toothed segment 201 and sliding of teeth 5211 over teeth 221 occur under a contact of metal to metal condition, without play or clearance of any nature or magnitude,, no matter how infinitely small, and without blocking or hampering said sliding motion of tool shank 5011 and of toothed segment 2011 which must occur under smooth rotation of micrometric screw 30,1.

once studs 621 are adjusted with proper load on Belleville springs (disc springs) 611, these springs store enough energy to eliminate an y clearance or play mentioned 1 above and to actuate as self-adjusting elements in the event there is slight wear that may occur af ter long use in the sliding surf aces and their respective seats, as well as in the flanks of teeth 52" and 221. After adjustment, studs 621 are locked by tightening lock stud 601.

The sliding action without clearance of tool shank 5011 and of toothed segment 20f in seats 21 and 11 respectively, the sliding action also totally free from any backlash between flanks of teeth 5211 and 221, the rotation of micrometric screw 301 without clearance in internal thread 21 and without axial clearance in the bearing consisting of inclined face 121 (provided in cylindrical cartridge 101) and face 4111 of ring 411, said sliding action without clearance guarantees the stability of the is position of edge of tool 51, so that radial distance GF-EG, GFO-EGI (drwg. 5) is assured within the micron _... said radial distance GF-EG, GFI-EW measured from the tool edge farthest point to the geometric axis of cylindrical cartridge 101, around which in a 3602 revolution of the tool, precision repeatability is assured in a constant way, until the tool wear occurs.

Still looking at drwg. 5, at each fraction of revolution of micrometric screw 301 corresponds a displacement of toothed segment 20f in a direction parallel to the axis of said micrometric screw 30f which is a function of thread pitch of this last one.

26 On its turn, at each displacement of toothed segment 201 along its geometric axis, corresponds a displacement of tool shank 5011, also along its geometric axis which is the function of the inclination angle P of teeth 52" and 221 in relation to the geometric axis of toothed segment 201.

Still, the displacement of tool shank 5011 consists of an axial displacement along the geometric axis of cylindrical cartridge 101 of limited interest, and of a radial displacement which determines the GFI-EG radius variation and, consequently, the diameter variation obtained with the setting. Such a radial displacement is the function of said displacement of tool shank 5011 and angle P. with which the sliding axis of tool shank 50" makes with the rotating axis of cylindrical cartridge 101 or angle with which the sliding axis of toothed segment 201 makes with the rotating axis of cylindrical cartridge 101.

Summing up and chronologically analyzing the degree of reading fineness in micrometric devices either for through or blind bores, the conclusion is that said degree of reading fineness of the devices depends essentially on the combination of two effects generated by two motion reduction systems or demultipliers constituting the referred combination of also referred two effects in a third and final effect.

27 1 The f irst ef f ect is the displacement of toothed segment 20, 201 along the axis direction of said micrometric screw 30, 30t obtained from one complete turn on graduated dial 43, 43f and as a consequence on micrometric screw 30, 30.' that can be mathematically represented by a quocient QI which is defined as being the ratio between the pitch thread in millimeters of micrometric screw 30, 301 and the number of divisions or lines of graduated dial 43, 431 being that said quociente QI represents an initial stage of displacement of toothed segment 20, 20f and which meanwhile said initial displacement is taking place in said toothed segment 20, 20' imposes a certain final displacement of tool shank 50, 50f, 5011 in a manner that a final displacement of said tool shank 50, 5V, 5011 results in a displacement equal to a fraction of the initial displacement of toothed segment 20, 20F as explained and defined below soon after the following example.

As an example "all if micrometric screw 30, 301 has a 0.5mm pitch and is connected to graduated dial 43, 431' that has 50 divisions (lines), it will enable a O.Olmm reading, that is, one hundredth of a millimiter of each division (line) in relation to the displacement imposed to toothed segment 20, 20,19, therefore QI is 0. 5150 O.Qlmm/line.

The second effect that can be mathematically represented by quocient QII, which is the ratio between the amount of displacement of toothed segment 20, 201 and the 28 "I 29 amount of radial displacement produced by this displacement on tool shank 50, 501, SO", and consequently on tool tip 51, 5V, being said quocient QII a function of angles and./3! and defined as being the resolution ratio of refinement or improvement of the system.

As another example "b" if the displacement of toothed segment 20, 20F is O.Olmm for each division (line) of graduated dial 43, 4V and if the radial displacement caused on tool shank 50, 50f, 50n is, for instance, 0. 0005mm for each division (line) the resolution ratio is represented by the expression 0.0110.0005 = 20 or 1:20, that is, to say that the radial displacement of tool tip 51, 511 is so many times smaller than the displacement of toothed segment 20, 201 as is the resolution ratio.

0 Angles -12 and P. are determined on a case by case basis by the sub-micron boring tool and pre-setting system design, therefore, for each application where and are determined, the resolution ratio is exclusively the function of angle P.

This means that by varying the angle according to the mathematical ratio that connects it to other parameters, any resolution ratio can be obtained, that is, a given amount of displacement of toothed segment 20, 201 causes a radial displacement to tool shank 50, 501, 5011 of an amount of greater or lesser magnitude of the amount of displacement of toothed segment 20, 201 in accordance with what might have been established as the value for angle 1 Said resolution ratio has been so called because it represents the resolution refinement of this system, that is, the ratio between the variation that can be obtained in the distance GF-EG, GFI-EGI and the displacement variation of toothed segment 20, 201. It should be remembered that the resolution refinement is nothing but the demultiplying ratio.

A third and final effect which, in other words, is the proper radial displacement caused on tool shank 50, 50f, 5011 and on tool tip 51, 511 obtained from the turn of graduated dial 43, 431 and, consequently, of micrometric screw 30, 3V, being said third effect an association of effects of the two previously described effects, which can be mathematically represente by a quocient QIII which is the ratio between quocients QI and Q=.

As a final example "c" if QI = 0.5150 = O.Olmnlline and if QII = 0.0110.0005 = 20, quocient QIII will be: QI/Q= = 0.01120 = 0.0005mm/line.

Considering that the sub-micron system subject of this invention is destined for the finish machining of ultra precision bores, allowing fine tool setting, that is to say allowing a very fine micrometric displacement of tool shank 50, 5V, 500 for a certain reading of the graduated dial, both in the version for finishing through bores drwgs. 1, 2, 3, 4, 4a and 4b and in the version for machining blind bores, drwgs. 5, 6 and 7, consequently, the amplitude of the field of machining AA.. is limited between the smallest and

31 the largest machinable diameters as shown in drwg. 8, because said amplitude of f ield of machining depends on the maximum permitted travel of tool shank 50, 50f, 5011 due to angle.0.X. of inclination of teeth to a required degree of precision.

Looking at drwgs. 8 and 9, to increase the amplitude of field of machining.(J. between the minimum and maximum machinable diameters, using a same sub-micron system, it is provided a system for clamping cutting tool

51, 511 where said tool 51, 511 is lodged in support 130 in "Ll' shape with a certain measure M at its rear side, which enables the machining of bores lying between diameters d and dI which once replaced by another support 131, see drwg. 9, enables the machining of bores lying between diameters dI and dII in the field' of machining U., reutilizing the feed f ield permitted by tool shank 50, 501, 5011 and so on using subsequent longer IILII shape supports.

The difference between measures M and MI being slightly smaller than the maximum travel permitted by tool shank 50, 501 and 50", makes possible the machining of any bore diameter lying between diameters d and d" by only replacing support 130 by support 131.

A plurality of supports in which the difference between M and MI are added to each new support, enables to repeat the enlargement of machining U. field a plurality of times.

1 is 32 Still in time, it is important to notice that the displacements of toothed segment 201 and tool shank 5011, as has been evidenced, proceed in a smooth way, are ultra precise, totally exempt from deviations (errors) or backlash, because the mating of flanks of male toothed segment 201 and male tool shank 5011 with the corresponding mating flanks of female seats 11 and 21, establishes an adequate condition totally free from backlash and that the GF-EG distance which corresponds to the radius described by the tool edge at its farthest or most distant point from its geometrical axis of rotation which can be chosen and selectively set. In this way, it is concluded to be axiomatically impossible that variation of any magnitude, nature or dimension occurs in the distance that corresponds to the radius described by the tool extreme edge at its farthest or most distant point from its geometric axis for any reason, fact or condition attributable to the sub-micron system as a whole or f or any reason, fact or condition attributable to one or more components taken separately.

In other words, once it is admitted that accomplishment of ultraprecision presupposes that a priori certain basic conditions are ensured, such as degree of environment cleanliness; strict temperature controlled ambient and vibration; and admitting also as practically negligible elastic deformation variations of the assembly that comprises the submicron system (once elastic deformations may account to mere few millionths of a 1 micron), remember that the reasons, facts or conditions to change the distance GF-EG, GPt-EGI that corresponds to the radius described by the tool farthest point on tool tip from its geometric axis of rotation are three, that is: 1. change and/or alteration in the position of geometric axis; 2. tool wear; and 3. change made by the operator or by a cause external to the sub-micron system by an action on the micrometric dial through knob rotation.

No other condition makes possible to change said GF-EG, GFIEGI distance within ultra precision standards, since the maximum permitted axial motion to the 'micrometric screw, added to the maximum permitted backlash between the thread of said screw and the thread of its nut,' results in negligible deviation of the tool edge in relation to its is rotational geometric axis.

Furthermore, it should be maximum backlash of 0.002mm between micrometric screw 30, 301 and rings 40, be reduced by utilizing the materials which said rings 40, 401, 41, 411, 42 submitted to compression through the 33 considered that the collar 35. 351 of 4V, 41, 41,1, 42 can elastic property of are made, which when proper tightening of screws 45, said maximum 0.002mm backlash can be progressively reduced to very minute amounts in the order of 0.000Imm tending towards zero.

And as explained above, taking into consideration that said maximum permitted 0.002mm backlash in the screw collar can be reduced to a small amount in the order of 0. 000lmm described rings 40, backlash (one tenth of the micron) through the already effect produced by said elastic deformation of 40, r 41, 411, 42 and that the maximum permitted or play between the thread of micrometric screw 30, 301 and its bushing 24, 241 can also be reduced through backlash suppression by acting on hollow stud 26, which also enables to reduce the backlash or play between micrometric 301 and bushing 24, 241 also down to an amount of of 0.000lmm (one tenth of the micron), it, follows requirement imposed by the definition of ultra precision class or precision degree, as it is accepted and understood within the present state-of-the-art. It is also important to point out that said effect produced by the peculiar elastic deformation of materials to which rings 40, 40,1, 41, 4111, 42 can be submitted, has been foreseen, duly considered and theoretically analyzed at the conception (design) stage and then evidenced by laboratory tests and research carried out that positively confirmed the validity of what was foreseen and previously considered.

Although a specific construction of a sub-micron boring tool and pre-setting system is described and illustrated, it should be pointed out that structural changes can be made without deviating from the scope of the present invention.

screw 30, the order that the 34

Claims (1)

1. A boring tool comprising a substantially cylindrical body having a first, substantially longitudinal bore therein, and a second bore opening in the circumferential surface of said body and intercepting said first bore, a tool shank for carrying a tool tip being movably received within said second bore, and a rotatable control knob carried by said body for enabling the position of the tool shank in said second bore to be set, and further comprising means provided in said first bore for moving said tool shank, said moving means being coupled to said control knob and being arranged to move said tool shank in said bore in response to rotation of said control knob.

2. A boring tool as claimed in Claim 1, wherein said moving means comprises a rotatable micrometric screw extending along said first bore, said micrometric screw being connected to said control knob at or near one end of the screw such that rotation of the control knob rotates the screw, and transmission means located within said first bore, said transmission means having an axial bore therethrough through which said micrometric screw extends, said screw being coupled to said transmission means such that rotation of the screw moves said transmission means, and said transmission means being coupled to said tool shank.

3. A boring tool as claimed in Claim 2, wherein said transmission means comprises a toothed segment arranged to be reciprocated by rotation of said micrometric screw, and wherein teeth of said toothed segment engage with 5 corresponding teeth on said tool shank.

4. A boring tool as claimed in any preceding Claim, wherein said micrometric screw is held positively within said first bore by one or more rings which are held in said first bore and prevented from axial movement in said first bore.

5. A boring tool as claimed in any preceding Claim, further comprising a bushing retained within said first bore, said bushing having an internal thread with which said transmission means is engaged.

6. A boring tool as claimed in any preceding Claim, further comprising resilient means for suppressing backlash of said tool shank, said resilient means being arranged to bias said tool shank substantially radially of said cylindrical body.

7. A boring tool as claimed in Claim 6, wherein said resilient means urge said tool shank radially inwardly.

8. A boring tool as claimed in any preceding Claim, further comprising means for preventing backlash in said movement of said tool shank, said backlash preventing means comprising a plunger slidable within an axial bore in said tool shank, said plunger carrying engagement means for engagement with said moving means.

9. An ultra-precision sub-micron boring tool and pre-setting system for through and/or blind bores, comprising cylindrical cartridge internally hollow with through bore, in the interior of which is lodged a toothed segment and a micrometric screw, both arranged on a common geometric axis, said micrometric screw being trespassed through an axial bore provided in the toothed segment and able to be engaged to internal thread provided with bushing, said bushing being lodged and retained by a hollow stud, the free end of the micrometric screw being enveloped by a set of rings that support said micrometric screw in relation to the cylindrical cartridge, wherein at its outer end the micrometric screw is attached to a graduated knob or dial through a locknut, wherein said cylindrical cartridge incorporates a second through bore located in preferably a right angle plane, which may however be inclined, in relation to the longitudinal axis of the first through bore, a tool shank being lodged in said second through bore, the tool shank being provided with a tool tip and with a backlash suppression system between the tool shank and the toothed segment, both comprising a movement demultiplier mechanism consisting of a rack type shaped indent arranged longitudinally in a secant plane to the body of toothed segment and with adequate inclination in relation to the geometric axis of the toothed segment, said indent being slidable coupled in a totally backlash free and selective manner on a corresponding indent provided in the secant plane of the tool shank.

10. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 9, wherein said micrometric screw is provided with a threaded portion on one of its ends which is trespassed through the axial bore provided in the toothed segment and meshes with the internal thread provided in the bushing, and said bushing is retained by the hollow stud in an extension, and is also lodged in the longitudinal bore of the cylindrical cartridge, and wherein the ring, spacer ring and ring supporting said micrometric screw rotating a control knob supported close to the external end of the micrometric screw, a fastening means defined as the locknut being threaded to the external threaded end of the micrometric screw and provided with a stud and pad, and wherein said second bore is located at a right angle to the longitudinal axis of said cylindrical cartridge, a recessed end of said cylindrical cartridge is provided for connection of an extended shank.

11. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 10, wherein said cylindrical cartridge is longitudinally hollow and has a stepped bore, being the diameter of a first portion of the bore being larger than the diameter of a second portion, and wherein in an intermediate portion of bore is defined the right angle bore which lodges the tool 5 shank.

12. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 11, wherein the rings supporting the micrometric screw are lodged in said first portion of the stepped bore provided in the cylindrical cartridge and wherein said micrometric screw is positively held axially, without any backlash, by screws that trespass said rings and are fastened in the bottom wall of said first portion.

13. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 12, wherein said micrometric screw incorporates a collar able to be fitted in a central opening of the spacer ring making possible rotating motion in relation to said micrometric screw through rotation control knob making said micrometric screw free to rotate, however, exempt from any axial displacement in relation to cylindrical cartridge.

14. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 13, wherein said micrometric screw incorporates near its external end a tapered seat around which the rotatable control knob is concentrically fitted by envelopment, the control knob being locked axially close to said tapered seat in a selective way and through the action of the locknut provided with a stud and pad.

15. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 14, wherein the control knob incorporates an indent in its face adjacent to an outer face of the cylindrical cartridge, the indent engaging a further indent provided in the face of a locating ring in a non positive detent fashion, the locating ring being lodged in a slidable manner at the end of said cylindrical cartridge and enveloped by a protection cover and constantly forced against the indent of the control knob by springs, said locating ring being radially retained by a pin.

16. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 15, wherein the rotating control knob incorporates an externally and peripherally graduated dial, and wherein a reference is determined by an index or reference point provided in a protection cover adjacent to said dial.

17. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 16, wherein the toothed segment is axially slidable relative to the cylindrical cartridge, said sliding being made by turning the control knob which in its turn is mounted on the micrometric screw, the displacement of said toothed segment being made in a selective manner in each of the directions of displacement.

18. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 17, wherein axial displacement of the toothed segment promotes displacement of the tool shank by way of the indent which possesses adequate inclination being meshed with the indent of the tool shank.

19. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 18, comprising a backlash suppression system comprising a resilient system lodged in a hole provided longitudinally in said tool shank, from one side said hole receiving a stud, and from the other side the hole receiving an end of a stud threaded in the hole provided in the cylindrical cartridge, the resilient system being trespassable to the interior of the tool shank through a hole provided therein, the resilient system being arranged between the end of the stud and the stud to constantly force the tool shank in one axial direction.

20. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 19, comprising a backlash suppression system between an indent of the toothed segment and an indent of the tool shank that perform in a positive manner instead of a resilient manner by way of an adjusting indented plunger lodged precisely, although slidable, in an axial bore provided internally in the body of the tool shank said indented plunger being provided with an indent coplanar to the indent of the tool shank, both indents actuating an indent of the toothed segment.

21. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 20, wherein adjustment displacement of the indented plunger in relation to the toothed segment and to the tool shank is accomplished by an adjusting stud threaded in the interior of the tool shank, which adjustment is made until simultaneous metal to metal contact occurs between opposite flanks of the indent with opposite flanks of the indented plunger and also with opposite flanks of the indent of the tool shank, keeping them metal to metal totally free from any backlash, however, enabling the toothed segment to slide smoothly in relation to the tool shank and indented plunger, said adjustment being locked by a lock stud threaded against the adjusting stud.

22. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 21, wherein stud travel in the interior of the tool shank causes travel of the indented plunger in the direction radially outwardly, while the body of the tool shank moves simultaneously in the opposite direction.

23. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 22, wherein the relative motion between the indented plunger and the tool shank is in opposite directions and actuates over opposite and inclined flanks of indentation of the toothed segment, and causes the withdrawal of the toothed segment radially and withdrawing of said plunger and said tool shank oppositely.

24. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 23, wherein rotation of the control knob mounted on micrometric screw causes displacement of the toothed segment axially under conditions of metal to metal contact between all moving and supporting surfaces, both acting as radial and axial bearings, assuring that the toothed segment displaces immune of any clearance, in such a way that an alternative motion clockwise and counterclockwise of the control knob of the extent of the space between two adjacent lines of rotating control knob, causes a displacement respectively in directions of the toothed segment equal to the quotient between the pitch of the micrometric screw and the number of lines (divisions) of the graduated dial, and by its turn, the indentation provided in the toothed segment contacts an indentation provided in the tool shank and simultaneously, also contacts an indentation provided in indented plunger, wherein said contact of the indentation of the toothed segment is made to assure that the flanks of the indentation of the toothed segment which contact flanks of the indentation provided in the tool shank are at all times opposite flanks to the flanks of the indentation of said toothed segment that contacts on flanks of the indentation provided in the indented plunger, so that advancing with stud in the interior of tool shank causes indented plunger to advance while simultaneously the tool shank advances in the opposite direction, which due to the special shape of the indents causes the withdrawing of the toothed segment and the withdrawing of the indented plunger and the tool shank.

25. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 24, wherein the toothed segment is unconditionally prevented from angular displacement in relation to cylindrical cartridge because the supports on opposite flanks of the indent of the toothed segment form a triangle with the centre of the micrometric screw, said contact of the indentation being made under a metal to metal condition such that at one point the contact is by one of the flanks of the indentation of the toothed segment meeting one of the flanks of the indent of the indented plunger, whilst at another point the contact is by an opposite flank of indentation of the toothed segment meeting a flank of the opposite side of the indentation of the tool shank, wherein when the stud is turned against the indented plunger, the plunger is forced to travel or to be displaced radially, while, simultaneously the tool shank is forced to travel or to be displaced in the opposite direction suppressing all backlash between all parts comprising the kinematics, assuring a metal to metal contact condition so that said contact points of the triangle lie on an secant plane parallel and common, coplanar to indentations respectively of the toothed segment, of the indented plunger and of the tool shank, which makes the toothed segment immune and prevents it from moving angularly at any extent or magnitude, even though at the lodging of bore where toothed segment slides in the interior of the cartridge the geometric shape of the periphery, that is, the section configuration of the toothed segment, as well as the geometric shape of the bore where the toothed segment is axially and slidable lodged, correspond to a substantially perfect circle because the contact between the indents of the parts is made at points located at a coplanar common plane which are in contact under a metal to metal condition totally free from any backlash and without interference.

26. An ultra-precision sub-micron boring tool and pre-sett ng system for through bores as claimed in Claim 25, wherein backlash suppression is accomplished by the separation of slidable components, toothed segment and tool shank until sliding of slidable components occurs in a way to assure that the sliding action takes place under metal to metal condition, without backlash, said separation being caused by the contact of special teeth flank profiles which, when in contact through forward travel of the stud in the interior of the tool shank, indented plunger also travels forward at the same time that the body of the tool shank travels in the opposite direction, the relative movement of the parts in opposite directions occurring due to the fact that flanks at one side of indentation of the tool shank and flanks of opposite sides of the indentation act respectively on flanks and opposite indentation and toothed segment causing the separation or withdrawal of toothed segment, and the separation or withdrawal of the parts being caused by metal to metal contact of special profiles of teeth flanks that are not parallel between themselves but converging, which may have the shape of a triangular prism or the shape of an involute or still any other shape in which the teeth thickness decreases as the profile approaches the converging point at the tooth tip, said contacts of converging profiles of indents being the cause of said separation or withdrawal, stopping the separation only when a metal to metal contact condition is established between the toothed segment and its contact location in the wall of lodging bore of bore of the cylindrical cartridge and also metal to metal contact is established between the tool shank and its contact location in the wall of lodging bore of bore of the cylindrical cartridge.

27. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claims 19 or 26, wherein an end of the cylindrical cartridge for connection to the extended shank is provided with a recessed portion forming a face of rest at right angle to its geometric axis from which projects externally threaded portion and centering portion.

28. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 27, wherein the free end of the micrometric screw incorporates concentrically an external face seat which makes possible the support of the device on a machine tailstock.

29. An ultra-precision sub-micron boring tool and pre-setting system for through bores as claimed in Claim 28, further comprising a balancing system for balancing rotating masses, having two blocks lodged in a slot provided in the cylindrical cartridge and positioned in a parallel secant plane in relation to the geometric axis of the bore provided in said cartridge, said blocks being provided with elongated openings trespassed by lock screws.

30. An ultra-precision sub-micron boring tool and U-F P9J5POT sNugT9 94Tsoddo BuTBaeAuoo BuTAeq >Peqs TOOZ 9q4 UOT40as SsOaO 9q4 '>Peqs T004 9q4 q4TM S90PJ s4T 90 9UO uT papTAoad xl4a94 o4 S409UUOD Aem BTqePTTS e UT XIDTqm qZ994 q4TM S9099 s4T 90 9UO UT P9PTAoad BuTaq 'S%UeTg 94Tsoddo Sz BUTBasAuoo sAsTdSTP UOTZOSS SsOaO OSOXIM OUSM69s P9'qZOOZ 9q4 UT Aem 9TqePTTS UT P9BPOT ST qDTqm 4e9s e BUTSTadmoo TS UlTeTO UT P9UlTPTO sp seaoq PUTTq ao; M94SAS BUT449s-ead Pue T004 BuTaOq uOaOTw-qns uOTsTo9ad-ea4Tn uv -ZS OE -STX19 PTL-S 11-,TM seTBUL> 5UTwa03: pulp a5p-pa4ago -rROTaPUTTAD en-: 30 STX9 oTa::emoeB uoT:4.R:-oa axl4 o::p uoT::peTaa uT pauTTouT R-4oq pue seATesmag: ueem::eq eTBue::nBTa:::pR pue::),ueoeppL> Bu-paq s::pmes PTRS ISI1UPTJ e::PTsoddo BUTBaSAU00 BUTARns UOT:P0es q:pTM S4Res ST 1q4TM MOTTOXI ST 4pn--p qBPT=,=RO TROTaPUTTAD R BUTSTadwoo mTeTo uT pawTeTo se saaoq PUM aog maZsAs BuT4::es-ead Pug TOO:: BuTaoq uoaoTm-qns uOTSTO6ad-R=4Tn uv -TE mai:c)s P Aq meaos p-res go pue OT etl4 49 peuezsRj 19Tp pe4RnpRaB pup meaos an::p .aoddns noTtIm sBuTa go 4es P pue 'Xuegs Too:: lpnzs MOTTOXI 9 Aq 4uauiBes Pan:4-004 R uT PguTuZea ATT9u=eZuT BuTaq BuTnsnq exj4 'BuTqsnq R JO Pgeag:- TRuaa4uT aRZ 04 PeTdnoo aq 04 STqe uoTzaod papRean4 9 n4Tm papTAoad BuTaq meaos oTa49woaoTw PTRS JsTXE 0TazamoeB ewes 9 UT PaBuRaaR meaDS 0Ta4amoaDTw R PuR 4uOw5es Pen4OWP R nZTm P6PTA0ad ATTRua64uT ST 95PT=ZJR0 TROTJPuTTAD PTRS uTsaggm JwTRTO 5uTP9OWd Aue uT pawTsTo su seaoq puTIq ao; meZsAs BUT44es-ead a second seat, said tool shank being provided with a cutting tool tip in one of its ends.

33. An ultra-precision sub-micron boring tool and pre-setting system of the blind type as claimed in Claim 32, wherein toothed segment and the tool shank display cross section with special profiles of flanks opposite to the face provided with teeth which are not parallel between themselves, but converging, and which cross section may have the triangular shape or an involute shape or a shape where the flanks are of unequal profiles or still of any other shape, whenever the distance between flanks of cross section measured parallel to the plane with teeth, will decrease as the measurement is made in parallel lines that approach the converging point opposite to the face provided with teeth of the respective toothed segment and of the tool shank, corresponding seats having sections suitable for adjustment to the special profiles of flanks of the toothed segment and the tool shank, that the corresponding mating flanks being under a metal to metal contact condition established by the fitting of the flanks of the male toothed segment and male flanks of the tool shank with corresponding mating female flanks of the seats, establishing finally the condition of adjustment totally free from backlash and free interference between mating flanks of the parts.

34. An ultra-precision sub-micron boring tool and pre-setting system for blind bores as claimed in Claim 33, wherein the toothed segment retains internally the bushing which connects an axially threaded end of the micrometric screw whose other end is provided with a collar a centering diameter and a centering projection, radially and axially supported by rings and inclined face, said rings being fastened by screws on the inclined face provided at end of the cylindrical cartridge and positioned at right angle to the first seat.

35. An ultra-precision sub-micron boring tool and pre-sett ng system for blind bores as claimed in Claim 34, wherein the support of the end of the micrometric screw is radially made by adjustment without clearance of the centering diameter in the bore of the ring and axially by retention without clearance of the collar between the face of the ring and an inclined face provided at the end of the cylindrical cartridge, the ring actuating as a spacer between said faces and said micrometric screw being thus supported and manually turnable through a fastening means defined by a thumb screw fastened at its free end by tightening which also fastens a graduated dial.

36. An ultra-precision sub-micron boring tool and pre-setting system for blind bores as claimed in Claim 35, wherein the toothed segment is slidable in relation to the cylindrical cartridge through rotating the graduated dial which in its turn is fastened to the micrometric screw, the displacement of said toothed segment being made in a selective way in each of the directions of displacement 37. An ultra-precision sub-micron boring tool and pre-setting system for blind bores as claimed in Claim 36, wherein displacement of the toothed segment in the directions that cause displacement of the tool shank in directions indirectly withdrawing or approaching tool tip from or to the geometric axis of rotation of the cylindrical cartridge are due to the fact that the indentation has been properly provided with an angle and properly meshing with the indentation of the tool shank.

38. An ultra-precision sub-micron boring tool and pre-setting system for blind bores as claimed in Claim 37, wherein a backlash elimination system comprises studs, each one pressing one disc spring over the face of the toothed segment, totally eliminating all backlash between the tool shank and its guide in the seat, also eliminating backlash between the toothed segment and its guide in the seat and eliminating backlash between the flanks of the indentations until a fitting condition is established of metal to metal, said fitting condition being positively assured by respective lock studs.

39. An ultra-precision sub-micron boring tool and pre-setting system for through or blind bores as claimed in Claims 26 or 38, wherein through indents respectively of the parts, when subjected to the stud, the indented plunger is pressed and compelled to travel radially at the same time that the tool shank travels in the opposite direction, until all sliding surfaces of the parts as well as the contact by resting on surfaces of bores and the sliding motion or travel is prevented from proceeding due to the metal to metal contact, making it impossible, without actuating rotating control knob of the micrometric screw any variation of distance, assuring that at each complete revolution of the tool tip, the precision of repetition or variation of distance is guaranteed to be within the micron range until tool tip wear occurs, and alternatively, due to the fact that through indentations respectively, of parts when subjected to pressure of studs actuating on resilient means and these actuating on male toothed segment cause it to displace in the direction of the surface where it slides in the interior of female seat under metal to metal contact condition, and also in the direction to approach indentation to indentation under metal to metal contact condition, respectively of parts until the flanks of male parts reach a condition of metal to metal contact at the flanks of female seat preventing any further movement due to the fact that metal to metal contact is achieved when all contact surfaces starting from the surface of contact of toothed segment subjected to pressure of parts are under metal to metal contact, assuring in this way that the maximum variation of the radial distances are contained under or within the micron range.

40. An ultra-precision sub-micron boring tool and pre-setting system for blind bores as claimed in Claim 39, wherein the backlash elimination is accomplished by the approach of the slidable components where toothed segment is properly pushed against tool shank until displacement of slidable components occurs in a way to assure that the sliding action occurs under metal to metal condition totally free from clearance due to the special configuration of cross section of toothed segment and tool shank which special profile of flanks opposite to the face provided with indents are not parallel between themselves, but converging, being that cross section of toothed segment and tool shank can be of a triangular shape or the shape of an involute or the shape where profiles are unequal or of any other shape whenever the distance between the flanks of the cross section, measured parallel to the indent, is decreasing as the measurement is made at parallel lines that are approaching the converging point opposite to the face provided with teeth of respective toothed segment of tool shank being that the configuration of the teeth with inclined flanks of both indents and can be of the shape of a triangular prism, or the shape of an involute, or still of any shape where the tooth thickness decreases as the tooth profile approaches the converging point at the tooth top, making possible that when the position of toothed segment is adjusted through studs each one pressing disc spring actuating on faces or flank of toothed segment, being that toothed segment under the action of energy stored by springs said toothed segment is continuously pushed against its sliding guide in seat which due to action of springs and in cooperation with the special geometric shape of section of said toothed segment and to the geometric shape of its sliding guide in bore, causes the generation of components of force that push toothed segment against tool shank and this one in its turn, due to the teeth profile of indentation of toothed segment that under proper pressure generated by springs is kept in mesh with teeth of indentation of tool shank in a way to eliminate any backlash between indentations and due to special geometric shape of indentations cause the generation of components of force that push tool shank against its guide in seat eliminating the backlash between tool shank and its guide in seat establishing a metal to metal sliding condition totally free from backlash of any nature or magnitude and without hampering sliding motion of tool shank and of toothed segment that through light and smooth manual operation of knob and thumb screw enables that micrometric screw rotates smoothly.

41. An ultra-precision sub-micron boring tool and pre-setting system for through and/or blind bores as claimed in Claims 29 or 40, wherein the tool shank provides a system of clamping cutting tool tip where this last one is lodged in replaceable support in the shape of letter "L" with a certain measure at its rear side enabling the machining of holes between diameters being that a plurality of supports in which the difference between isadded to each new support enable to repeat the enlargement of the machining field a plurality of times.

42. An ultra-precision sub-micron boring tool and pre-setting system for through and/or blind bores as claimed in Claim 41, wherein the backlash elimination is accomplished by utilizing the existence of indentations provided at the tool shank and at the toothed segment, which special profile of teeth flanks are not parallel between themselves but converging, which may have the shape of a triangular prism or the shape of an involute or still any other shape in which the thickness of tooth decreases as the profile approaches the converging point at the tooth top.

43. An ultra-precision sub-micron boring tool and pre-setting system for through and/or blind bores, as claimed in Claim 42, wherein the ratio between the thread pitch of the micrometric screw and the graduation on knob or dial determines a first quotient.

44. An ultra-precision sub-micron boring tool and pre-setting system for through and/or blind bores as claimed in Claim 43, wherein the quotient between the amount of displacement of toothed segment in relation to its micrometric screw and the amount of radial displacement occurred on the tool shank and consequently on the tool tip in relation to the geometric axis of the cylindrical cartridge determines a second quotient which is the demultiplying ratio or resolution ratio of the sub-micron system.

45. An ultra-precision sub-micron boring tool and pre-setting system for through and/or blind bores as claimed in Claim 44, wherein the amount obtained by the first quotient divided by the second quotient determines a third quotient that is, the effect on the tool tip resulting from the rotation of the dial which promotes the variation of distance between the tool tip and the geometric axis of the cylindrical cartridge.

46. An ultra-precision sub-micron boring tool and pre-setting system for through and/or blind bores as claimed in Claim 45, wherein the construction concept of the micrometric screw, of its collar and of the rings enable that when properly tightened by screws, the resulting adjustment deriving from elastic deformation on rings absorbs the residual axial micro backlash on collar of the micrometric screw in order to reduce said micro backlash to an amount in millimeters within a range of onetenth of the micron or even smaller than this range, with tendency to reach zero backlash.

47. A boring tool substantially as hereinbefore described with reference to the accompanying drawings.